(1) Field of the Invention
The present invention relates to a shoe sole having a fluid filled apparatus which reacts with the stimulus of an outside force, hereinafter referred to as Reactive Energy Fluid Filled Toroid Apparatus, contained in its midsole. In particular, the present invention provides a shoe sole having a toroid apparatus comprising concentric fluid filled toroids contained in its midsole, the toroid apparatus providing cushioning and stability to the shoe sole.
(2) Description of the Related Art
Many soles of shoes, in particular athletic shoes, require a certain amount of cushioning to absorb the shock of footstep impact in walking, running and other activities, and thereby provide some protection to the shoe wearer's foot. This is most evident in the heels of many athletic shoes, the heel portion of the shoe sole typically being the first portion of the sole to impact with the ground during running. To a somewhat lesser extent, cushioning is also required in the arch and forefoot areas of shoe soles. However, merely adding additional cushioning to the heel of a shoe sole has been found to be insufficient to protect the foot in several respects.
In running, the initial impact of a shoe sole on each footstep is typically along the outer, lateral edge of the runner's heel. As the cushioning of the shoe sole heel gives under the force of the footstep impact, the force of impact is concentrated on the lateral edge of the runner's heel and is not distributed over the entire heel surface. The initial impact on the outer edge of the runner's heel also tends to cause the rotation of the foot relative to the leg, or a lowering of the medial margin of the foot, commonly known as pronation. Excessive pronation is thought to be related to many different injuries of the foot.
During walking, running or other activities it is also possible that initial impact on the lateral border of the shoe sole will be followed by supination of the foot or the raising of the medial margin of the foot. As the shoe cushioning gives under impact, the force of impact is concentrated on the lateral edge of the heel and is not distributed over the heel surface. Excessive supination of the foot is commonly thought to be related to different injuries of the foot and ankle.
What is needed to overcome the above-described disadvantages of prior art athletic shoes is an apparatus that cushions the sole of the shoe, causing the forces due to each footstep impact to be distributed over a greater area of the foot than just the lateral or medial edges of the foot. What is also needed to overcome the above-described disadvantages is an apparatus in a shoe sole that stabilizes the foot in the shoe and reduces the tendency of the runner's ankle to bend in pronation or supination with each footstep impact.